| abstract |
Prepn. of unsaturated diesters by catalytic gas phase reaction of a conjugated diene, a carboxylic acid, and O2. The catalyst used contains Pd, V, Sb, >=1 alkali metal carboxylate and opt. an alkali metal halide. The catalyst has better activity, selectively, stability and life than prior art Pd contg. catalysts. In an example, a catalyst comprising a 1:1:1 mixt of Pd, V and Sb on a silica-alumina carrier, promoted with K acetate, was used to convert a 20:20:60 (vol) mixt of butadiene acetic acid, and air at 140 degrees C. There was more than 95% conversion into diacetoxybutene, with high selectivity (>95%) for 1,4-diacetoxy-butene-2. |